TY - JOUR
T1 - Constitutive AP-1 activity and EBV infection induce PD-l1 in Hodgkin lymphomas and posttransplant lymphoproliferative disorders
T2 - Implications for targeted therapy
AU - Green, Michael R.
AU - Rodig, Scott
AU - Juszczynski, Przemyslaw
AU - Ouyang, Jing
AU - Sinha, Papiya
AU - O'Donnell, Evan
AU - Neuberg, Donna
AU - Shipp, Margaret A.
PY - 2012/3/15
Y1 - 2012/3/15
N2 - Purpose: Programmed cell death ligand 1 (PD-L1) is a molecule expressed on antigen-presenting cells that engages the PD-1 receptor on T cells and inhibits T-cell receptor signaling. The PD-1 axis can be exploited by tumor cells to dampen host antitumor immune responses and foster tumor cell survival. PD-1 blockade has shown promise in multiple malignancies but should be directed toward patients in whom it will be most effective. In recent studies, we found that the chromosome 9p24.1 amplification increased the gene dosage of PD-L1 and its induction by JAK2 in a subset of patients with classical Hodgkin lymphoma (cHL). However, cHLs with normal 9p24.1 copy numbers also expressed detectable PD-L1, prompting analyses of additional PD-L1 regulatory mechanisms. Experimental Design: Herein, we utilized immunohistochemical, genomic, and functional analyses to define alternative mechanisms of PD-L1 activation in cHL and additional EBV+ lymphoproliferative disorders. Results: We identified an AP-1-responsive enhancer in the PD-L1 gene. In cHL Reed-Sternberg cells, which exhibit constitutive AP-1 activation, the PD-L1 enhancer binds AP-1 components and increases PD-L1 promoter activity. In addition, we defined Epstein-Barr virus (EBV) infection as an alternative mechanism for PD-L1 induction in cHLs with diploid 9p24.1. PD-L1 was also expressed by EBV-transformed lymphoblastoid cell lines as a result of latent membrane protein 1-mediated, JAK/STAT-dependent promoter and AP-1-associated enhancer activity. In addition, more than 70% of EBV+ posttransplant lymphoproliferative disorders expressed detectable PD-L1. Conclusions: AP-1 signaling and EBV infection represent alternative mechanisms of PD-L1 induction and extend the spectrum of tumors in which to consider PD-1 blockade.
AB - Purpose: Programmed cell death ligand 1 (PD-L1) is a molecule expressed on antigen-presenting cells that engages the PD-1 receptor on T cells and inhibits T-cell receptor signaling. The PD-1 axis can be exploited by tumor cells to dampen host antitumor immune responses and foster tumor cell survival. PD-1 blockade has shown promise in multiple malignancies but should be directed toward patients in whom it will be most effective. In recent studies, we found that the chromosome 9p24.1 amplification increased the gene dosage of PD-L1 and its induction by JAK2 in a subset of patients with classical Hodgkin lymphoma (cHL). However, cHLs with normal 9p24.1 copy numbers also expressed detectable PD-L1, prompting analyses of additional PD-L1 regulatory mechanisms. Experimental Design: Herein, we utilized immunohistochemical, genomic, and functional analyses to define alternative mechanisms of PD-L1 activation in cHL and additional EBV+ lymphoproliferative disorders. Results: We identified an AP-1-responsive enhancer in the PD-L1 gene. In cHL Reed-Sternberg cells, which exhibit constitutive AP-1 activation, the PD-L1 enhancer binds AP-1 components and increases PD-L1 promoter activity. In addition, we defined Epstein-Barr virus (EBV) infection as an alternative mechanism for PD-L1 induction in cHLs with diploid 9p24.1. PD-L1 was also expressed by EBV-transformed lymphoblastoid cell lines as a result of latent membrane protein 1-mediated, JAK/STAT-dependent promoter and AP-1-associated enhancer activity. In addition, more than 70% of EBV+ posttransplant lymphoproliferative disorders expressed detectable PD-L1. Conclusions: AP-1 signaling and EBV infection represent alternative mechanisms of PD-L1 induction and extend the spectrum of tumors in which to consider PD-1 blockade.
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U2 - 10.1158/1078-0432.CCR-11-1942
DO - 10.1158/1078-0432.CCR-11-1942
M3 - Article
C2 - 22271878
AN - SCOPUS:84858206832
SN - 1078-0432
VL - 18
SP - 1611
EP - 1618
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 6
ER -